Application of an Integrated Management Approach to the Restoration Project of the Lagoon of Venice

摘要

The lagoon of Venice is suffering major environmental problems which affect both its morphological and ecological characteristics, such as disappearance of tidal marshes owing to erosion processes and extensive macroalgal blooms due to high nutrient loads. In order to reverse this environmental deterioration, the Consorzio Venezia Nuova (CVN) has undertaken a programme to restore the morphology and improve the. quality of the lagoon by designing practical measures to be implemented within the lagoon boundaries, as well as providing management tools to analyse different management measures. An integrated management approach was adopted to fulfil this objective, taking into account all the aspects of the environmental problems and their relationships with the economic activities in the estuary and its catchment. The main steps and specific tools of this approach are the following: 1. description of the lagoon ecosystem; 2. identification of the main aspects of the degradation; 3. identification of critical environmental parameters and definition of target conditions for the recovery plan; 4. verification of the selected target conditions and identification of critical areas using Geographic Information System (GIS) techniques; 5. assessment of the effectiveness of the most promising restoration measures using (hydrodynamic and water quality) mathematical models; 6. evaluation of intervention alternatives in relation to their technical and economical feasibility and their socio-economic impact. The results obtained using this approach have shown that the restoration process of the lagoon can be implemented only through the realisation of an integrated set of measures over different time scales. Long term measures include the reduction of pollution inputs from the drainage basin; medium term measures include modification of the morphology and of the water circulation pattern in specific areas; and emergency actions include macro-algae harvesting. This analytical approach is the basis of a decision support system that will be developed for the future management of the lagoon. It will help in defining monitoring programs, evaluating intervention options, and evaluating impacts of planned socio-economic development. This approach can be applied in any other geographical context.